Abstract 157 – Population estimation of Gobi brown bear and their movement in the Great Gobi A Strictly Protected Area, Mongolia

Battogtokh Nasanbat, Francisco Ceacoero, Petr Matějů, Ariunbuyan Khurelbaatar,
Barbora Černá Bolfíková, Samiya Ravchig

Robust population estimation of rare or elusive threatened species lacking distinct identifiable
features poses a challenge in the field of conservation and management. The Gobi brown bear
(Ursus arctos) is one of such species living in geographically isolated and inaccessible harsh
desert areas of Great Gobi A Strictly Protected Area. Population size is one of the primary
parameters determining urgency of conservation action, and it provides baseline data against
which to measure progress toward recovery. We designed a camera-based approach to
estimate population during period of greater activity of the bear from June to September at the
main 13 natural springs in the whole protected area based on our previous study and also
combined with meta-barcoding analysis based on hair samples 2022 and 2024. We used criteria
to identify individual Gobi brown bears based on shoulders-mark patterns and tested the level
of congruence among 3 independent observers using a set data of photographs collected in
2018, 2020, 2022 and 2024.
We grouped the main 13 natural springs into three mountain ranges: Tsagaan Bogd, Shark
Khulst, and Atas Inges mountains. In 2018, 4451 pictures were evaluated by the researchers,
and average congruence among observers resulted in 33-36 individuals. Only 4 males and 1
female were observed in more than one mountain ranges. In 2020, 1094 pictures of the brown
bear have been evaluated and average congruence among observers resulted in 27-31
individuals: 10-12 adult males, 6-8. Only 3 males were observed in more than one mountain
ranges. In 2022, the average congruence among observers resulted in 22-25 individuals. Only 1
male was observed in more than one mountain ranges. We will carry out similar survey this
year (2024) and will also collect hair samples. The molecular biological analyses on the hair
samples are still in progress and results will be presented at the conference combining different
sampling techniques.